Coal spreader unit



Sept. 16, 1941. B, ow 2,255,841

COAL SPREADER UNI'T Filed NOV. 21, 1938 2 Sheets-Sheet l Sept. 16, 1941.

B. F. BOWER COAL SPREADER UNIT 2 Sheets-Sheet 2 Filed Nov. 21, 1958 @7072 ffiower Patented Sept. 16, 1941 2,255,841 COAL SPREADER UNIT Byron F. Bower, St. Charles, Ill.,,assignor to The Howell Company, St. Charles, 111., a corporation of Illinois Application November 21, 1938, Serial No. 241,483

' 3 Claims.

The present invention relates to fuel feeding devices for feeding coal and similar fuels into the fire box of a furnace. It is the principal purpose of this invention to provide an improved structure for distributing the coal within the furnace by means of a rotating spreader to which fuel is fed from a hopper by a reciprocating pusher block.

In devices of this character, the coal from the hopper is fed to a deflector housing where it is engaged by a series of paddles on a rotor shaft and thrown into the fire box. The housing which receives the coal from the pusher element in the bottom of the hopper usually has what is termed a deflector plate portion at the bottom thereof. In order to sweep this deflector plate clean, it is essentialthat the paddles of the rotor fit closely to the deflector plate. On the other hand, the paddles must not bind against the deflector plate, as this would wear them continuously and throw an excessive load on the operating unit which drives the rotor. It is the fundamental purpose of this invention to provide anovel construction for the rotor and deflector plate whereby the proper clearance may be readily maintained between the paddles of the rotor and the deflector plate surface.

It is also a purpose of the present invention to provide a structure of this character wherein sifting of the coal around the pusher block which feeds coal to the rotor is substantially eliminated.

In certain forms of mechanical spreader fuel feeding devices, such as that shown in the present application, considerable difficulty is encountered in the protection of the rotor and its shaft from 1 the intense heat of the furnace. Various water cooled devices are employed with resultant complications because of the necessity for water connections to the rotor parts. 'The present invention contemplates a novel cooling system whereby the rotor with its paddles is subjected to a continuous stream of cooling air and thus protected from overheating.

Other and more detailed advantagesof the invention will appear more fully as the description proceeds, reference being had'to the accompanying drawings wherein a preferred form of the invention is-shown. It is to be understood, however, that the drawings and description are illustrative only and are not to be taken as limiting the invention except insofar as it is limited by the claims.

In the drawings,

Fig. 1 is a vertical sectional view taken through (Cl. 1l.0-115) device of the so-called mechanical spreader stoker type wherein a rotating paddle wheel is used to throw the fuel into the furnace. and spread it over the fire box grate area. In the present invention, as illustrated, there is a door casting 5 bolted to a metal front facing 6 of the furnace by means of a series of bolts I. This door casting 5 forms the support for a fuel feeding unit 8. The fuel feeding unit comprises a hopper 9, a reciprocating pusher I 0, and a defiector housing I! having a deflector plate portion l2 from which the fuel is swept into the furnace by a rotor IS. A base plate I4 is provided beneath the pusher H3, which also has an agitator bar l5 for breaking up the coal in the hopper as the pusher block Ill is reciprocated.

The deflector plate portion I2 'is directly above and over fire door [6, a portion of which is shown in Fig. 1., Arrangement is made whereby air can be directed against the lower surface I! of the deflector plate'portion I 2. This is done to keep the deflector plate cooled and to prevent rapid deterioration thereof. The entire fuel feeding mechanism is supported on the door casting 5 by means of two side frames l8 and H) which are connected by cross frame members 26 and 2|. The cross frame member '20 has cars 22 thereon and is bolted directly to the casting 5 'by means of a plurality of bolts 23. Adjusting screws 28 are utilized to control the position of the fuel feeding mechanism with respect to the fuel entrance provided in the door castingS. The side frames are welded to the member 20.

The door casting 5 is provided with an interior lining 25 of a refractory material. This lining is precast in the door casting and is adapted to protect the casting and the fuel feeding mechanism supported thereby from the heat within the firebox.

The side frames 18 and I 9 extend up outside of the lower edges of the hopper 9. As shown best in Figs. 1 and 4, the hopper has side lip portions 26 which extend down over corresponding side walls 21 of the pusher block frame. 'The hopper portion has its front and back edges 28 and 29 extending down inside the cross frame members 29 and 2|. Thus it is evident that sifting of coal dust around the bottom of the hopper portion is prevented. The hopper 9 has a shelf portion 39 which keeps the coal from falling between the agitator plate l5 and the frame member 20. The cross frame member 2| has an adjustable scraper 3| which rides on the pusher block i so as to keep dust from sifting out on top of the pusher block.

The pusher block I0 and the agitator plate |5 are cast integral with the side walls 21. The mounting of the cross frame member 2| is by flanges 2|a and 2|b which extend over the side walls 21. The pusher block is operated by a rock shaft 32 and an arm 33 which carries a roller 34 at its upper end. The roller 34 fits between two depending lugs 35 and 36 on the under side of the pusher block Ill. The base plate I4 is riveted to the side frames I8 and I9. This base plate has 'on its under surface a curved depending lip 31 which co-operates with a portion 38 of the deflector housing II to prevent coal sifting below the base plate M. The base plate I 4 also has a depending lug 39 to which one end 40 of a turn buckle 4|.is pivoted. The other end 42 of the turn buckle is pivoted to a lug 43 on the deflector Thehousing H is supported upon two bushings 44 and 45. The bushing 44 is mounted in an opening 42, one-half of which is formed in the casting 5 and th other half of which is formed 'in the-side frame l8. The bushing 45 is mounted in a similar opening provided jointly by the casting 5 and the side frame l9. The casting II has end walls 46 and 41 which are slotted as shown at 48 to permit the entry of a rotor shaft 49. The

slot 48,'of course, communicates with an opening that is large enough to receive the bushings 44 and'45.: It is to be understood, of course, that there is a slot 48 in each of the end walls 46' and 41. s

The rotor I3 is composed of the shaft 49 which is hollow, being preferably constructed of a ma-.

small motor.

justment of the shaft 49 so as to govern the engagement of the paddles 55 and 56 with the deflector plate I2. Clean sweeping of the deflector plate requires that the paddles 55 and 56 be adjusted rather closely, and the present invention provides a novel construction whereby this adjustment may be absolutely controlled so that the paddles neither bind nor ride too loosely on the deflector plate l2. As the paddles become worn and the plate becomes worn, the mounting is such that the wear may be readily compensated for without disturbing the driving connections for the shaft 49.

The shaft 49 is mounted in two bearings 59 and 60. These bearings are formed in the ends of two supporting arms 6| and 62 respectively. The hollow shaft 49 is connected rigidly to a stub shaft 63 that projects through a gear housing 64 and is coupled by a universal joint 65 to a suitable drive shaft 66. The drive shaft 66 may be driven from any suitable source, such as a The stub shaft 63 has a pinion 61 thereon which meshes with a gear 68. The gear 68 is keyed to a shaft 69 which is journalled in *|8 and I9. At the end opposite the gear 68 the terial capable of withstanding a high heat without rapid deterioration such, for example, as a chromium steel alloy. This hollow shaft 49 has a;multiplicity.of openings between the end wa11s46 and 41 of the deflector housing II. It also has openings 5| and 52 outside the side frames l8 and I9 so' as to permit air to enter through the shaft'49. The shaft 49 is also spaced from the bushings 45 and 44 so that air may enter between the bushings and the shaft.

On the shaft 49 there are mounted a series of collars 53'which collars are bored to receive two shafts 54 and 55. The collars 53 also space the coal throwing paddles 56 and 51. As shown, the paddles 56' and 51 are arranged in two opposite groups, one'group being adapted to throw the Short lugs 58 are provided on the paddles to limit their movement in the reverse direction.

The shaft 49 is not ,carried by the bushings '44.and 45. Ample space is provided between the space. 49 "and the bushings to permit vertical ad- 'air through'the shaft 49.

shaft 69 has an eccentric connection to a link 12, which, in turn, is connected to the rock shaft 32 for actuating the pusher block H1. The particular connection between the link 12 and the shaft 32 forms the subject matter of my copending application, Serial No. 240,721 filed November 16, 1938, for Fuel feed control mechanism. The de-, tails of. this structure are not important to the present invention.

The arms 6| and 62 are journalled upon the sleeve 1|. The arm 6| is held by an upper lug 13' and a lower lug 14 provided on the side frame l9. Adjusting screws 15 and 16 determine the position of the arm 6|. Similarly, the arm 62 is held between an upper lug 11 and a lower lug 18 by suitable screws 19 and 80. It will be evident that, by turning the arms 6| and 62 on the sleeve 1|, the shaft can be raised or lowered within the limits provided by the bushings 44 and 45. The adjusting screws 15, 16, 19 and 86 enable one to position the rotor shaft 49 with a fine degree of accuracy. This shifting of the shaft 49 does not disturb the meshing of the pinion 61 and the gear 68 because the adjustment is made about the axis of the gear 68 as a center. The housing 64 of course turns with the arm 62 as it is connected to this arm. 7

1 The bearings 59 and 6|], only one of which is shown in section; include suitable ball bearings for the shaft 49. It will'be noted that the bearings are beyond the openings 5| and 52 so that Whatever heat reaches the bearings is that con ducted through the material of the shaft, and most of the heat is carried away by the flow of V The bearing 60 includes a mounting head 8| upon which the housing 64 is fitted.

' alloy of the nature of stainless steel. This mate- 'rial wears well and is capable of standing considerable heat without losing its strength. I have provided only two sets of paddles, as I have found this to be more effective from the fuel feeding standpoint than the usual four paddles provided n this type of construction. The reason for this is that the paddles are moving at a relatively high rate of speed and do not move any substantial amount of coal upon each rotation. They will, therefore, be less apt to break up the coal particles if they are spaced 180 than they would if they were spaced 90. In addition, the coal being fed into the deflector housing has a better opportunity of spreading before it engages the paddles. The fewer number of paddles lightens the load on the shaft 49.

The rotation of the paddles within the deflector housing ll tends to throw air centrifugally outward and to thus create a vacuum to draw air into the deflector housing through the shaft $9. This vacuum also draws air into the housing between the shaft 49 and the bushings 44 and 45. I have found that this air cooling is effective to maintain the shaft and its paddles at a sufficiently low operating temperature to prevent serious deterioration thereof.

From the foregoing description it is believed that the features and advantages of my invention will be readily apparent to those skilled in this art. Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a mechanical spreader type of fuel feeding device for furnaces, a hopper, a frame supporting said hopper, a deflector plate in said frame below and laterally offset from said hopper, a shaft carried by said frame and extending across the frame over the deflector plate, bearings for said shaft on the exterior of said frame, a pusher block beneath said hopper, a second shaft journalled on said frame, means operatively connecting said second shaft to the pusher block, a gear and pinion connecting said shafts, spreader paddles on said first named shaft, and means for adjusting said paddles with respect to the deflector plate, said means comprising arms pivotally supported by said frame for movement about the axis of said second shaft, said bearings being carried by said arms, and means on the frame for holding the arms in a position to which they are adjusted.

2. In a mechanical spreader type of fuel feeding device for furnaces, a hopper, a frame supporting said hopper, a deflector plate in said frame below and laterally offset from said hopper, a shaft carried by said frame and extending across the frame over the deflector plate, bearings for said shaft on the exterior of said frame, a pusher block beneath said hopper, a second shaft journalled on said frame, means operatively connecting said second shaft to the pusher block, a gear and pinion connecting said shafts, spreader paddles on said first named shaft, and means for adjusting said paddles with respect to the deflector plate, said means comprising arms pivotally supported by said frame for movement about the axis of said second shaft, said bearings being carried by said arms, means on the frame for holding the arms in a position to which they are adjusted, and a housing for said gear and pinion, said housing being carried by one of said arms.

3. In a mechanical spreader type of fuel feeding device for furnaces, a frame having spaced side portions, a deflector plate in said frame, a shaft extending across the frame and through the side portions, spreader means on said shaft adapted to advance fuel from the deflector plate into the furnace, said side portions having openings therein larger than said shaft to permit adjustment of the shaft and spreader means toward and away from the deflector plate, bearings for said shaft, said bearings being spaced outwardly from said side portions, a fuel feeding device in :said frame for feeding fuel to said spreader means, a second shaft journalled in said frame and operatively connected to said fuel feeding means, a gear and pinion connecting said shafts, supporting arms for said bearings, said arms being pivotally supported by said side portions about the axis of said second shaft, and means on said side portions for holding the arms in a position to.

which they are adjusted.

BYRON F. BOWER. 

